Discussion:
Diagnosis of SARS‐CoV‐2 is done by RTPCR testing . However, there is limited availability and high cost of RTPCR testing for SARS‐CoV‐2, in addition to its potentially high false negative rate of patients clinically diagnosed with COVID‐19. Furthermore, the RT‐PCR results
showed a fluctuating trend (4). The timely transfer patients to ICU or a designated unit (isolation or quarantine) that has sufficient rescue equipments should be considered even if their results of RT‐PCR test for pharyngeal swab specimens are negative to limit the spread of infection.
Therefore, the need for rapid bed-side diagnostic tools is highly appreciated. In this study we put for the first time a high sensitive score for suspicion of SARS‐CoV‐2 infection using bed-side investigation tools as chest X ray and lung ULS. A single clinician would be necessary to perform an initial medical assessment and imaging investigation directly at the patient’s bed.
Lung ULS can help in reducing the number of health care professionals exposed during patient stratification by simple rapid bed side test (14)(15).
Lung ULS could be done without patient immobilization that might spread the infection. This differs from CT chest that requires patient mobilization and may be difficult in critical ventilated patients, in addition to its radiation hazards and high cost.
To the best of our knowledge, there is only one case report describing the findings of lung ULS in confirmed Covid 19 patient and reporting an irregular pleural line with small subpleural consolidations, areas of white lung and thick, confluents and irregular vertical artifacts (B-lines)(15).
Although our findings carry variable findings, however our results found that A profile and abnormal A lines in lung ULS are independent predictors for Covid 19 infection.
Our score has high sensitivity (93.8%) in detection of Covid 19 infection making it a good negative test.
Lung ULS was reported to have 86% diagnostic accuracy in detecting alveolar con­solidation and was able to differentiate between effusion and consolidation. Its specificity for detecting consolidation reached 100% in some studies (11).
Regarding the prognosis of Covid 19 infected patients, we analyzed the predictors for mortality as long as prolonged hospitalization. Old age, presence of cardiac problem and hypoxia on admission are clinical predictors of mortality. This is concordant with previous reports (7)(16).
Concerning lung ULS, we present for the first time imaging predictors for mortality using this simple, safe and cheap tool in Covid 19 patients.
In our study B lung ULS profile and abnormal A lines were associated with mortality.
Abnormal A lines was also correlated with prolonged hospitalization. This also may direct the medical staff to determine patients needing high care and those that may need long hospital stay.
Regarding other investigation, CT chest shows more consolidation and ground glass appearance in Covid 19 infected patients. This is consistent with other reports in which the prominent radiologic abnormalities were bilateral
ground-glass opacity and subsegmental consolidation areas (8)(17).
Our laboratory findings showed that Covid 19 infected patients had less blood O2 saturation and less lymphocytic count than other causes of pneumonia. However, in our study lymphopenia has not reach the significant degree of correlation with mortality. Other reports showed predominance of lymphopenia in Covid 19 infection among critical than other less critical patients and is associated with severe course (7)(18). In a study conducted with Zhou et al, they found that baseline lymphocyte count was significantly higher in survivors than non-survivors of Covid 19 infected patients. However in survivors,
lymphocyte count improved after the 1st week of illness, whereas severe
lymphopenia remained until death in non-survivors(7).